Vargas-Rodriguez , L., Herrera, J., Morales, E., Arcos-Garcia, J., Lopez-Pozos, R., & Ruelas, G. (2015). Effect of Citric Acid, Phytase and Calcium in Diets of Laying Hens on Productive Performance, Digestibility and Mineral Excretion. International Journal of Poultry Science, 14(4), 222–228. https://doi.org/10.3923/ijps.2015.222.228